June 2021
Volume 62, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2021
Organelle distribution of the human retinal pigment epithelium (RPE) in age-related macular degeneration (AMD)
Author Affiliations & Notes
  • Leon von der Emde
    Ophthalmology, University Hospital Bonn, Bonn, Germany
  • Katharina Bermond
    Ophthalmology, Ludwigshafen Hospital, Ludwigshafen, Germany
  • Iona-Sandra Tarau
    Ophthalmology, University Hospital Würzburg, Würzburg, Germany
  • Leonie Bourauel
    Ophthalmology, University Hospital Bonn, Bonn, Germany
  • Rainer Heintzmann
    Biological nanoimaging, Leibniz Institute of Photonic Technology, Jena, Germany
    Institute of physical Chemistry and Abbe Center of Photonics, Friedrich-Schiller University Jena, Jena, Germany
  • Frank G Holz
    Ophthalmology, University Hospital Bonn, Bonn, Germany
  • Christine A Curcio
    Ophthalmology, University of Alabama at Birmingham, Alabama, Alabama, United States
  • Kenneth R Sloan
    Ophthalmology, University of Alabama at Birmingham, Alabama, Alabama, United States
  • Thomas Ach
    Ophthalmology, University Hospital Bonn, Bonn, Germany
  • Footnotes
    Commercial Relationships   Leon von der Emde, None; Katharina Bermond, None; Iona-Sandra Tarau, None; Leonie Bourauel, None; Rainer Heintzmann, None; Frank Holz, Acucela (C), Acucela (R), Allergan (F), Apellis (C), Bayer (C), Bayer (R), Bioeq/Formycon (F), Bioeq/Formycon (C), Boehringer-Ingelheim (C), CenterVue (F), Ellex (R), Geuder (C), Grayburg Vision (C), Heidelberg Engineering (C), IvericBio (C), Kanghong (C), LinBioscience (C), NightStarX (F), Novartis (C), Optos (F), Oxurion (C), Pixium Vision (C), Roche/Genentech (C), Stealth BioTherapeutics (C), Zeiss (R); Christine Curcio, Genentech (F), Heidelberg Engineering (F), MacRegen Inc (I); Kenneth Sloan, None; Thomas Ach, MacRegen Inc (I), Novartis (F), Novartis (R), Roche (C)
  • Footnotes
    Support  NIH/NEI 1R01EY027948-01
Investigative Ophthalmology & Visual Science June 2021, Vol.62, 3279. doi:
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      Leon von der Emde, Katharina Bermond, Iona-Sandra Tarau, Leonie Bourauel, Rainer Heintzmann, Frank G Holz, Christine A Curcio, Kenneth R Sloan, Thomas Ach; Organelle distribution of the human retinal pigment epithelium (RPE) in age-related macular degeneration (AMD). Invest. Ophthalmol. Vis. Sci. 2021;62(8):3279.

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      © ARVO (1962-2015); The Authors (2016-present)

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Purpose : Human RPE cells contain numerous lipofuscin (LF), melanolipofuscin (ML), and melanosome (M) organelles that vary in number with retinal location (fovea, perifovea, and near periphery) and age (PMID: 32433758) as well as impact on clinical autofluorescence (AF) imaging. Here, we examined the effect of AMD on granule count and AF of RPE cell bodies.

Methods : Seven AMD-affected human RPE flatmounts (early: 3, late dry: 1; neovascular: 3) were imaged at three locations (fovea, perifovea, near periphery) using structured illumination microscopy (SIM) and confocal AF (both: excitation 488 nm). Z-stacks (step size: SIM 100 nm, confocal 390nm) were acquired from apical to basal through RPE cell bodies of 10 adjacent cells in each region. Subsequently, LF, ML, and M were marked, counted, and classified based on their AF properties using a customized ImageJ plug-in. AF/cell was calculated from confocal images. Furthermore, we analysed the impact of AMD on the total number of granules and AF/cell implementing a mixed effect ANCOVA, correlated granule count with cell size, and compared the results with data from normal RPE cells (PMID: 32433758).

Results : Of 152 RPE cells analyzed, average granule count/cell was 449 ± 276 LF, 532 ± 377 ML, and 4 ± 2 M, with early AMD demonstrating higher average granule count (987 ± 616) and lower LF (406 ± 287) compared with late-stage AMD manifestations. While there was a high variation in granule load among cells, the foveal RPE cells had lowest LF (194 ± 290) and total granule count (851 ± 917). AMD-affected RPE cells were larger than RPE cells in normal eyes, had a higher granule density (granules/µm2), but showed significantly lower AF at all three locations (fovea: < 0.01; perifovea: 0.02; near periphery: <0.01).

Conclusions : The reduced histological AF signal in AMD eyes compared to healthy cells mirrors and helps to explain clinical AMD AF imaging. Enlarged AMD affected RPE cells might reflect cell fusion or failed cytokinesis (PMID 26875723), which increases net granule count and diminishes total AF. Interestingly, LF was lowest at the fovea typically affected by accumulation of drusen in AMD as well as preservation of cone-mediated visual acuity. Here, we examined RPE cell bodies, but future studies should also focus on M within RPE’s apical processes and their impact on RPE AF imaging (PMID 32648890).

This is a 2021 ARVO Annual Meeting abstract.


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